The cook-tops mentioned herein are preferably though not exclusively intended for domestic use. They comprise a plurality of localized cooking sections for receiving kitchen utensils whose contents are to be heated. The heating means generally comprise elements for heating by the Joule effect, by radiation or by induction. During use the heating element must be turned on, the power consumption must be adjusted, in some cases several times, and finally the heating element must be turned off.
When the utensil is lifted briefly the user does not necessarily intend to stop the operation of the heating element. This may have different consequences:
Therefore, it is desirable that the operation of the heating element can be controlled during said actions. Obviously, this should not have any consequences for the operation of the other heating elements.
U.S. Pat. No. 4,499,368 describes a system for detecting a removal of a utensil from a cook-top. For this purpose a time is measured during which the temperature of the utensil exceeds a threshold temperature. If this time exceeds a predetermined time the electric power supply to the cook-top is interrupted. The predetermined time intervals are adapted depending on whether the cook-top has been programmed for frying, boiling, stewing, etc. The time intervals are of the order of 10 to 20 minutes. These values are dictated by the requirement to preclude operation of a cook-top without a utensil or with an empty utensil.
However, such a cook-top does not provide any control of the operation during brief interruptions.
In the art of cooking there are several cases in which it is necessary to remove a pan briefly from a heating source, after which it is put back. If the user wishes to avoid the consequences of said radiation the heating element may be deactivated and may subsequently be reactivated by hand. This procedure soon turns out to be tedious.
The problem to be solved is to provide an automatic on/off function which precludes the adverse effects of said radiation when a utensil is removed temporarily. This automatic function should be effective, i.e. it should correctly distinguish the situation in which the utensil is removed temporarily and is subsequently put back from other situations and should respond accordingly.